Deriving Population Growth Models by Growing Fruit Fly Colonies

2016 ◽  
Vol 78 (3) ◽  
pp. 221-225 ◽  
Author(s):  
Aaron J. Heaps ◽  
Tyler D. Dawson ◽  
Jace C. Briggs ◽  
Megan A. Hansen ◽  
Jamie L. Jensen

Population growth presents a unique opportunity to make the connection between mathematical and biological reasoning. The objective of this article is to introduce a method of teaching population growth that allows students to utilize mathematical reasoning to derive population growth models from authentic populations through active learning and firsthand experiences. To accomplish this, we designed a lab in which students grow and count populations of Drosophila over the course of 12 weeks, modifying abiotic and biotic limiting factors. Using the data, students derive exponential and logistic growth equations, through mathematical reasoning patterns that allow them to understand the purpose of these models, and hypothesize relationships between various factors and population growth. We gathered student attitudinal data and found that students perceived the lab as more effective, better at preparing them for lecture, and more engaging than the previous lab used. Through this active and inquiry-based method of teaching, students are more involved and engaged in both mathematical and biological reasoning processes.

2018 ◽  
Author(s):  
Emanuel A. Fronhofer ◽  
Lynn Govaert ◽  
Mary I. O’Connor ◽  
Sebastian J. Schreiber ◽  
Florian Altermatt

AbstractThe logistic growth model is one of the most frequently used formalizations of density dependence affecting population growth, persistence and evolution. Ecological and evolutionary theory and applications to understand population change over time often include this model. However, the assumptions and limitations of this popular model are often not well appreciated.Here, we briefly review past use of the logistic growth model and highlight limitations by deriving population growth models from underlying consumer-resource dynamics. We show that the logistic equation likely is not applicable to many biological systems. Rather, density-regulation functions are usually non-linear and may exhibit convex or both concave and convex curvatures depending on the biology of resources and consumers. In simple cases, the dynamics can be fully described by the continuous-time Beverton-Holt model. More complex consumer dynamics show similarities to a Maynard Smith-Slatkin model.Importantly, we show how population-level parameters, such as intrinsic rates of increase and equilibrium population densities are not independent, as often assumed. Rather, they are functions of the same underlying parameters. The commonly assumed positive relationship between equilibrium population density and competitive ability is typically invalid. As a solution, we propose simple and general relationships between intrinsic rates of increase and equilibrium population densities that capture the essence of different consumer-resource systems.Relating population level models to underlying mechanisms allows us to discuss applications to evolutionary outcomes and how these models depend on environmental conditions, like temperature via metabolic scaling. Finally, we use time-series from microbial food chains to fit population growth models and validate theoretical predictions.Our results show that density-regulation functions need to be chosen carefully as their shapes will depend on the study system’s biology. Importantly, we provide a mechanistic understanding of relationships between model parameters, which has implications for theory and for formulating biologically sound and empirically testable predictions.


Author(s):  
Yusri Fefiani ◽  
Pandu Prabowo Warsodirejo

This study aims to: 1) recognize fruit flies (Drosophila melanogaster), 2) morphologically distinguish adult fruit fly sex, 3) study the growth of fruit fly populations. The practicum was held on August 20, 2019 in the Biology Education Laboratory FKIP UISU. The working principle of practicum is making food as a medium for fruit fly culture (a mixture of bananas, cassava tape, benzoate), etherization and observation, observing the growth of fruit fly populations. Observations were made by counting the number of live flies and dead flies, the sex ratio of flies. Observations were carried out every day, for 15 days (20 August 2019 - 3 September 2019). The results of the analysis show that: 1) population growth of Drosophila melanogaster includes logistic growth models with S-shaped curves, 2) sex of adult fruit flies can be morphologically distinguished through body size, abdominal shape, genital comb and external genital organs in the abdomen. Based on the results and discussion, the following conclusions are obtained: 1) fruit flies including insects undergoing perfect metamorphosis (egg phase, larvae, pupa, imago), 2) differences in adult fruit fly sex can be seen from body size, abdomen shape, presence of genital comb, external genital organs in the abdomen, 3) population growth of fruit flies including logistic growth models in the form of S curves, influenced by environmental factors


2020 ◽  
Vol 13 (06) ◽  
pp. 2050051
Author(s):  
Zhinan Xia ◽  
Qianlian Wu ◽  
Dingjiang Wang

In this paper, we establish some criteria for the stability of trivial solution of population growth models with impulsive perturbations. The working tools are based on the theory of generalized ordinary differential equations. Here, the conditions concerning the functions are more general than the classical ones.


2006 ◽  
Vol 11 (4) ◽  
pp. 425-449 ◽  
Author(s):  
James H. Matis ◽  
Thomas R. Kiffe ◽  
Timothy I. Matis ◽  
Douglass E. Stevenson

1971 ◽  
Vol 78 (8) ◽  
pp. 841 ◽  
Author(s):  
W. G. Costello ◽  
H. M. Taylor

1984 ◽  
Vol 21 (2) ◽  
pp. 225-232 ◽  
Author(s):  
Abebe Tessera

In the familiar immigration–birth–death process the events of immigration, birth and death relate to the individual. There are processes in which the whole family and not just an individual migrates. Such population growth models are studied in some detail.


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